Reland "Implement an explicit binary search-based analytic gradient colorizer"

This reverts commit 9461dcf1306a9a9517e1545cf6d16bde05261280.

Reason for revert: Fixes for ANGLE's incorrect shader behavior

Original change's description:
> Revert "Implement an explicit binary search-based analytic gradient colorizer"
>
> This reverts commit dcc85fc61008f61daef4313846bdd62877fd596d.
>
> Reason for revert: ANGLE is frequently corrupted, particularly radial_gradient4 and mixershader
>
> Original change's description:
> > Implement an explicit binary search-based analytic gradient colorizer
> >
> > Provides a reasonably flexible fragment processor that defines another
> > colorizer implementation for gradients. It can support up to 8
> > interpolation intervals (which is 16 colors if every stop is a hard stop
> > or 9 colors if every stop is a smooth transition). It
> > supports mixtures of hard and smooth stops. It is conditionally compiled
> > into versions specific to the interval count (so it can produce up to
> > 8 shader variants).
> >
> > The GrGradientShader controller does not remove the single and dual
> > interval colorizers, which are useful specializations of this explicit
> > binary search colorizer. Similarly, since it can only handle up to 8
> > intervals, the texture colorizer is still used as a fallback.
> >
> > Currently it does not employ capabilities detection to determine if the
> > hardware can support the number of required uniforms, which can become
> > substantial for the larger gradient configurations.
> >
> > Bug: chromium:796479, chromium:729727, chromium:696603, chromium:543625, chromium:414254
> > Change-Id: Ia1f735a5019766ae4796cc22964b2913db34b95b
> > Reviewed-on: https://skia-review.googlesource.com/155080
> > Commit-Queue: Michael Ludwig <michaelludwig@google.com>
> > Reviewed-by: Brian Osman <brianosman@google.com>
>
> TBR=bsalomon@google.com,brianosman@google.com,michaelludwig@google.com
>
> Change-Id: I351a387f0528e4c2db2d47ab2e5d6b336991fb98
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: chromium:796479, chromium:729727, chromium:696603, chromium:543625, chromium:414254
> Reviewed-on: https://skia-review.googlesource.com/156541
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>
> Commit-Queue: Michael Ludwig <michaelludwig@google.com>

TBR=bsalomon@google.com,brianosman@google.com,michaelludwig@google.com

Change-Id: I2aca36307d88c26905d860ec29417ec68c6037cc
Bug: chromium:796479, chromium:729727, chromium:696603, chromium:543625, chromium:414254
Reviewed-on: https://skia-review.googlesource.com/156542
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
9 files changed